This invention relates to an indicating device for an electronic flash unit, and, more particularly, to an indicating device for computer type electronic flash unit (said computer type electronic flash unit is hereinafter abbreviated to electronic flash unit).
It is known to provide a so-called computer type electronic flash unit receptive of the reflected light from an object being photographed by a photoelectric element and responsive to the attainment of the amount of integrated light to a predetermined level for stopping the flash tube from further firing.
With such electronic flash unit, the photographer cannot recognize whether or not the amount of flash light emitted is adequate when in flash photography, because the flash unit automatically controls the flash light value in itself.
On this account, it has been proposed to use a device for indicating the detection of whether or not the electronic flash unit has produced an adequate amount of flash light, in other words, whether or not an amount of flash light necessary to derive a correct flash exposure has been emitted from the discharge tube (said device is hereinafter referred to as "indicating device for electronic flash unit") in Japanese patent application Laid-Open Specification No. Sho 47-17427.
In the indicating device for electronic flash unit according to said proposal, however, because of the necessity of providing for said indication with an additional signal terminal arranged in the electronic flash unit, there are disadvantages such that the complexity of structure of the electronic flash unit is increased, and such that the reliability is largely lowered.